Presence of Human Metapneumovirus Associated with Severe Acute Respiratory Syndrome Corona Virus-2 and Corresponding Cytokine Levels in Human Patients

Respiratory viruses lead to severe mortality and morbidity worldwide. There is a continuous eruption of new and already existing viruses throughout the year. To understand the occurrence of co-infection of Human Metapneumovirus (HMPV) and Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2) leading to severity in patients. Real-time reverse transcriptase-polymerase chain reaction was conducted on nasopharyngeal swab samples from patients infected with respiratory-like illness. The primers for two respiratory viruses, HMPV and SARS-CoV-2, were used for amplification. 9.9% of the samples were found to be infected with HMPV, and of these, 88.8% were also infected with SARS-CoV-2. The fluctuations in cytokine levels were also correlated, and it was found that interferon levels were low during mixed infection. We also report that while HMPV infection does not induce a hyperinflammatory effect, as a mixed infection with SARS-CoV-2, it could inhibit the adaptive immune responses due to reduced secretion of interferon-gamma, leading to insufficient sensitisation for B cells to produce antigen-specific response antibodies.